The present invention relates to a circuit board assembling structure which is applied to an electric junction box or the like, and adapted to assemble a wiring circuit board on which electric wires are arranged and a bus bar circuit board on which bus bars are arranged thereby to constitute a circuit board assembly.
FIG. 3 shows one example of a conventional circuit board assembling structure for an electric junction box, which is disclosed in Japanese Patent Publication No. 9-140028A (cf., page 3 and FIG. 2).
This electric junction box 51 includes a plurality of bus bar circuit boards 52 to be stacked one on another, and a wiring circuit board 53 disposed below the bus bar circuit boards 52. The bus bar circuit boards 52 and the wiring circuit board 53 constitute a circuit board assembly, and upper and lower covers 54 and 55 made of synthetic resin contain the circuit board assembly.
Each of the bus bar circuit boards 52 includes a plurality of bus bars 56 made of conductive sheet metal in desired shapes, and an insulative substrate 57 on which the bus bars 56 are arranged. The bus bars 56 are provided with tab terminals 58 which are continuously extended from their end portions or intermediate portions. The terminals 58 are received in connector housings 59 of the upper cover 54 thereby to constitute a connector, or connected to fuses and relays in the upper cover by way of relay terminals 60 of a female type.
The wiring circuit board 53 includes a plurality of electric wires 61, and a case 62 made of insulative resin on which the electric wires 61 in desired shapes are arranged. Each of the electric wires 61 is press-fitted to one contact portion 63a of a terminal 63 at a desired position inside the case. The other contact portion 63b of the terminal 63 is passed through a hole 64 of the case 62 to be connected to a terminal of the bus bar 56, or passed through the lower cover 55 to be received in connector housings below the lower cover 55.
The bus bars 56 are mainly suitable for a large current circuit such as a power source circuit, and the electric wires 61 are mainly suitable for a small or middle current circuit such as a signal circuit. The bus bars 56 and the electric wires 61 are connected to each other so that an electric power can be supplied to the connector of the lower cover 55. Exterior wire harnesses (not shown) continued to the power source and an auxiliary equipment are connected to the connectors of the upper and lower covers 54, 55.
However, in the above described configuration, since the bus bar circuit boards 52 and the wiring circuit board 53 are stacked in a direction of their thickness, the more specifications of the circuits becomes complicated, the more the circuit board assembly become upsized in a vertical direction, so that the electric junction box 51 accordingly become large-sized. Further, since the bus bar circuit boards 52 has to be assembled to the wiring circuit board 53 after the wiring board 53 is assembled to the lower cover 55, a lot of working steps are required in assembling the circuit board assembly, that is, the electric junction box 51.